
/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_HTTP_UPSTREAM_H_INCLUDED_
#define _NGX_HTTP_UPSTREAM_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#include <ngx_event_connect.h>
#include <ngx_event_pipe.h>
#include <ngx_http.h>


#define NGX_HTTP_UPSTREAM_FT_ERROR           0x00000002
#define NGX_HTTP_UPSTREAM_FT_TIMEOUT         0x00000004
#define NGX_HTTP_UPSTREAM_FT_INVALID_HEADER  0x00000008
#define NGX_HTTP_UPSTREAM_FT_HTTP_500        0x00000010
#define NGX_HTTP_UPSTREAM_FT_HTTP_502        0x00000020
#define NGX_HTTP_UPSTREAM_FT_HTTP_503        0x00000040
#define NGX_HTTP_UPSTREAM_FT_HTTP_504        0x00000080
#define NGX_HTTP_UPSTREAM_FT_HTTP_404        0x00000100
#define NGX_HTTP_UPSTREAM_FT_UPDATING        0x00000200
#define NGX_HTTP_UPSTREAM_FT_BUSY_LOCK       0x00000400
#define NGX_HTTP_UPSTREAM_FT_MAX_WAITING     0x00000800
#define NGX_HTTP_UPSTREAM_FT_NOLIVE          0x40000000
#define NGX_HTTP_UPSTREAM_FT_OFF             0x80000000

#define NGX_HTTP_UPSTREAM_FT_STATUS          (NGX_HTTP_UPSTREAM_FT_HTTP_500 \
                                              |NGX_HTTP_UPSTREAM_FT_HTTP_502 \
                                              |NGX_HTTP_UPSTREAM_FT_HTTP_503 \
                                              |NGX_HTTP_UPSTREAM_FT_HTTP_504 \
                                              |NGX_HTTP_UPSTREAM_FT_HTTP_404)

#define NGX_HTTP_UPSTREAM_INVALID_HEADER     40


#define NGX_HTTP_UPSTREAM_IGN_XA_REDIRECT    0x00000002
#define NGX_HTTP_UPSTREAM_IGN_XA_EXPIRES     0x00000004
#define NGX_HTTP_UPSTREAM_IGN_EXPIRES        0x00000008
#define NGX_HTTP_UPSTREAM_IGN_CACHE_CONTROL  0x00000010
#define NGX_HTTP_UPSTREAM_IGN_SET_COOKIE     0x00000020
#define NGX_HTTP_UPSTREAM_IGN_XA_LIMIT_RATE  0x00000040
#define NGX_HTTP_UPSTREAM_IGN_XA_BUFFERING   0x00000080
#define NGX_HTTP_UPSTREAM_IGN_XA_CHARSET     0x00000100


typedef struct {
  ngx_msec_t                       bl_time;
  ngx_uint_t                       bl_state;

  ngx_uint_t                       status;
  time_t                           response_sec;
  ngx_uint_t                       response_msec;
  off_t                            response_length;

  ngx_str_t                       *peer;
} ngx_http_upstream_state_t;


typedef struct {
  ngx_hash_t                       headers_in_hash;
  ngx_array_t                      upstreams;
  /* ngx_http_upstream_srv_conf_t */
} ngx_http_upstream_main_conf_t;

typedef struct ngx_http_upstream_srv_conf_s  ngx_http_upstream_srv_conf_t;

typedef ngx_int_t (*ngx_http_upstream_init_pt)(ngx_conf_t *cf,
                                               ngx_http_upstream_srv_conf_t *us);
typedef ngx_int_t (*ngx_http_upstream_init_peer_pt)(ngx_http_request_t *r,
                                                    ngx_http_upstream_srv_conf_t *us);


typedef struct {
  ngx_http_upstream_init_pt        init_upstream;
  ngx_http_upstream_init_peer_pt   init;
  void                            *data;
} ngx_http_upstream_peer_t;


typedef struct {
  ngx_addr_t                      *addrs;
  ngx_uint_t                       naddrs;
  ngx_uint_t                       weight;
  ngx_uint_t                       max_fails;
  time_t                           fail_timeout;

  unsigned                         down:1;
  unsigned                         backup:1;
} ngx_http_upstream_server_t;


#define NGX_HTTP_UPSTREAM_CREATE        0x0001
#define NGX_HTTP_UPSTREAM_WEIGHT        0x0002
#define NGX_HTTP_UPSTREAM_MAX_FAILS     0x0004
#define NGX_HTTP_UPSTREAM_FAIL_TIMEOUT  0x0008
#define NGX_HTTP_UPSTREAM_DOWN          0x0010
#define NGX_HTTP_UPSTREAM_BACKUP        0x0020


struct ngx_http_upstream_srv_conf_s {
  ngx_http_upstream_peer_t         peer;
  void                           **srv_conf;

  ngx_array_t                     *servers;  /* ngx_http_upstream_server_t */

  ngx_uint_t                       flags;
  ngx_str_t                        host;
  u_char                          *file_name;
  ngx_uint_t                       line;
  in_port_t                        port;
  in_port_t                        default_port;
};


typedef struct {
  ngx_http_upstream_srv_conf_t    *upstream;

  ngx_msec_t                       connect_timeout;
  ngx_msec_t                       send_timeout;
  ngx_msec_t                       read_timeout;
  ngx_msec_t                       timeout;

  size_t                           send_lowat;
  size_t                           buffer_size;

  size_t                           busy_buffers_size;
  size_t                           max_temp_file_size;
  size_t                           temp_file_write_size;

  size_t                           busy_buffers_size_conf;
  size_t                           max_temp_file_size_conf;
  size_t                           temp_file_write_size_conf;

  ngx_bufs_t                       bufs;

  ngx_uint_t                       ignore_headers;
  ngx_uint_t                       next_upstream;
  ngx_uint_t                       store_access;
  ngx_flag_t                       buffering;
  ngx_flag_t                       pass_request_headers;
  ngx_flag_t                       pass_request_body;

  ngx_flag_t                       ignore_client_abort;
  ngx_flag_t                       intercept_errors;
  ngx_flag_t                       cyclic_temp_file;

  ngx_path_t                      *temp_path;

  ngx_hash_t                       hide_headers_hash;
  ngx_array_t                     *hide_headers;
  ngx_array_t                     *pass_headers;

  ngx_addr_t                      *local;

#if (NGX_HTTP_CACHE)
  ngx_shm_zone_t                  *cache;

  ngx_uint_t                       cache_min_uses;
  ngx_uint_t                       cache_use_stale;
  ngx_uint_t                       cache_methods;

  ngx_flag_t                       cache_lock;
  ngx_msec_t                       cache_lock_timeout;

  ngx_array_t                     *cache_valid;
  ngx_array_t                     *cache_bypass;
  ngx_array_t                     *no_cache;
#endif

  ngx_array_t                     *store_lengths;
  ngx_array_t                     *store_values;

  signed                           store:2;
  unsigned                         intercept_404:1;
  unsigned                         change_buffering:1;

#if (NGX_HTTP_SSL)
  ngx_ssl_t                       *ssl;
  ngx_flag_t                       ssl_session_reuse;
#endif

  ngx_str_t                        module;
} ngx_http_upstream_conf_t;


typedef struct {
  ngx_str_t                        name;
  ngx_http_header_handler_pt       handler;
  ngx_uint_t                       offset;
  ngx_http_header_handler_pt       copy_handler;
  ngx_uint_t                       conf;
  ngx_uint_t                       redirect;  /* unsigned   redirect:1; */
} ngx_http_upstream_header_t;


typedef struct {
  ngx_list_t                       headers;

  ngx_uint_t                       status_n;
  ngx_str_t                        status_line;

  ngx_table_elt_t                 *status;
  ngx_table_elt_t                 *date;
  ngx_table_elt_t                 *server;
  ngx_table_elt_t                 *connection;

  ngx_table_elt_t                 *expires;
  ngx_table_elt_t                 *etag;
  ngx_table_elt_t                 *x_accel_expires;
  ngx_table_elt_t                 *x_accel_redirect;
  ngx_table_elt_t                 *x_accel_limit_rate;

  ngx_table_elt_t                 *content_type;
  ngx_table_elt_t                 *content_length;

  ngx_table_elt_t                 *last_modified;
  ngx_table_elt_t                 *location;
  ngx_table_elt_t                 *accept_ranges;
  ngx_table_elt_t                 *www_authenticate;
  ngx_table_elt_t                 *transfer_encoding;

#if (NGX_HTTP_GZIP)
  ngx_table_elt_t                 *content_encoding;
#endif

  off_t                            content_length_n;

  ngx_array_t                      cache_control;

  unsigned                         connection_close:1;
  unsigned                         chunked:1;
} ngx_http_upstream_headers_in_t;


typedef struct {
  ngx_str_t                        host;
  in_port_t                        port;
  ngx_uint_t                       no_port; /* unsigned no_port:1 */

  ngx_uint_t                       naddrs;
  in_addr_t                       *addrs;

  struct sockaddr                 *sockaddr;
  socklen_t                        socklen;

  ngx_resolver_ctx_t              *ctx;
} ngx_http_upstream_resolved_t;


typedef void (*ngx_http_upstream_handler_pt)(ngx_http_request_t *r,
                                             ngx_http_upstream_t *u);


struct ngx_http_upstream_s {
  ngx_http_upstream_handler_pt     read_event_handler;
  ngx_http_upstream_handler_pt     write_event_handler;

  ngx_peer_connection_t            peer;

  ngx_event_pipe_t                *pipe;

  ngx_chain_t                     *request_bufs;

  ngx_output_chain_ctx_t           output;
  ngx_chain_writer_ctx_t           writer;

  ngx_http_upstream_conf_t        *conf;

  ngx_http_upstream_headers_in_t   headers_in;

  ngx_http_upstream_resolved_t    *resolved;

  ngx_buf_t                        buffer;
  off_t                            length;

  ngx_chain_t                     *out_bufs;
  ngx_chain_t                     *busy_bufs;
  ngx_chain_t                     *free_bufs;

  ngx_int_t                      (*input_filter_init)(void *data);
  ngx_int_t                      (*input_filter)(void *data, ssize_t bytes);
  void                            *input_filter_ctx;

#if (NGX_HTTP_CACHE)
  ngx_int_t                      (*create_key)(ngx_http_request_t *r);
#endif
  ngx_int_t                      (*create_request)(ngx_http_request_t *r);
  ngx_int_t                      (*reinit_request)(ngx_http_request_t *r);
  ngx_int_t                      (*process_header)(ngx_http_request_t *r);
  void                           (*abort_request)(ngx_http_request_t *r);
  void                           (*finalize_request)(ngx_http_request_t *r,
                                                     ngx_int_t rc);
  ngx_int_t                      (*rewrite_redirect)(ngx_http_request_t *r,
                                                     ngx_table_elt_t *h, size_t prefix);
  ngx_int_t                      (*rewrite_cookie)(ngx_http_request_t *r,
                                                   ngx_table_elt_t *h);

  ngx_msec_t                       timeout;

  ngx_http_upstream_state_t       *state;

  ngx_str_t                        method;
  ngx_str_t                        schema;
  ngx_str_t                        uri;

  ngx_http_cleanup_pt             *cleanup;

  unsigned                         store:1;
  unsigned                         cacheable:1;
  unsigned                         accel:1;
  unsigned                         ssl:1;
#if (NGX_HTTP_CACHE)
  unsigned                         cache_status:3;
#endif

  unsigned                         buffering:1;
  unsigned                         keepalive:1;

  unsigned                         request_sent:1;
  unsigned                         header_sent:1;
};


typedef struct {
  ngx_uint_t                      status;
  ngx_uint_t                      mask;
} ngx_http_upstream_next_t;


typedef struct {
  ngx_str_t   key;
  ngx_str_t   value;
  ngx_uint_t  skip_empty;
} ngx_http_upstream_param_t;


ngx_int_t ngx_http_upstream_header_variable(ngx_http_request_t *r,
                                            ngx_http_variable_value_t *v, uintptr_t data);

ngx_int_t ngx_http_upstream_create(ngx_http_request_t *r);
void ngx_http_upstream_init(ngx_http_request_t *r);
ngx_http_upstream_srv_conf_t *ngx_http_upstream_add(ngx_conf_t *cf,
                                                    ngx_url_t *u, ngx_uint_t flags);
char *ngx_http_upstream_bind_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
                                      void *conf);
char *ngx_http_upstream_param_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
                                       void *conf);
ngx_int_t ngx_http_upstream_hide_headers_hash(ngx_conf_t *cf,
                                              ngx_http_upstream_conf_t *conf, ngx_http_upstream_conf_t *prev,
                                              ngx_str_t *default_hide_headers, ngx_hash_init_t *hash);


#define ngx_http_conf_upstream_srv_conf(uscf, module)   \
  uscf->srv_conf[module.ctx_index]


extern ngx_module_t        ngx_http_upstream_module;
extern ngx_conf_bitmask_t  ngx_http_upstream_cache_method_mask[];
extern ngx_conf_bitmask_t  ngx_http_upstream_ignore_headers_masks[];


#endif /* _NGX_HTTP_UPSTREAM_H_INCLUDED_ */
